Time-based surgeries: These can be further divided into 3 categories- elective, semi-elective and emergency surgery. An elective surgery is conducted to cater to a non-life threatening condition and is done at consent of the patient and the availability of the surgeon and the respective facility. A semi-elective is one that can be delayed for a later point of time but not too long as it may then cause a loss of life or limb. An emergency surgery is one that must be conducted immediately to save life, body parts or functionality.
Body-parts: Some surgeries draw their identity from the area on which it is being conducted, to simplify further, the organs or tissues. For example, those to do with the heart falls under the realm of cardiac surgery, hepatology for liver, orthopedic for bones and so on.
Based on invasiveness: Based on the magnitude of incision in order to get access to the concerned area. Some surgeries require large incisions as in the cases of open-heart surgeries whereas some, like in angioplasties work by introducing small instruments through small outer incisions.
Equipment-based: Different surgeries call for different equipments. Lasers can be used to cut tissues, burn tumors; scalpel is the conventional surgical equipment. Nowadays robotic hands are also used in surgery, directed by a surgeon. The Zeus surgical system is an example of the latter.